Most computerized air-to-ground weapon delivery systems have at least two delivery modes. One is manual release or continuously computed impact point (CCIP) mode. The other is an automatic release mode, also referred to as dive-toss or continuously computed release point (CCRP).
In the manual or CCIP mode, the computer displays the resulting impact point if weapon release were to occur at the present time. The pilot steers the aircraft so as to overlay the target with this impact point symbol. He then depresses the weapon release button which manually triggers the weapon release.
In the dive-toss or automatic mode, the computer displays a target marker symbol or pipper which is elevated above the computed impact point. This elevation or lead angle is necessary so that the target marker symbol will pass the target in advance of the release time. The pilot steers the aircraft so as to overlay the target with the pipper and then depresses a "target designation" or "pickle" switch. This action signals the computer to record all available target sensor information such as the line-of-sight azimuth and depression angles, slant range, and altitude. From these data the computer calculates the target location and generates steering signals which direct the pilot to steer the computed impact pilot toward the target. As the computed impact point crosses the computed target position, the computer automatically issues a weapon release signal.
The term "dive-toss" as applied to this delivery mode comes about because the pilot, after designating the target in a dive, usually pulls back hard on the control stick to initiate a high g pullup. By this pullup maneuver the pilot gets rid of the bomb as soon as possible. He can then initiate evasive action to avoid antiaircraft fire.
If the pipper position is short of the computed impact point (negative lead angle), the aircraft would already be past the release point when the pilot designated the target. On the other hand, if the pipper position is above the horizon, the pilot cannot position it over the target, which is presumably on the ground. By this line of reasoning, the weapon delivery system must position the target marker somewhere between the impact point and the horizon.
Some currently operational weapon delivery systems set the elevation coordinate of the target marker to zero depression. Others match the depression angle of the target marker to that of the aircraft's velocity vector. As for the azimuth coordinate, most of these current systems employ a drift stabilized sight. That is, the target marker symbol lies in the azimuthal plane of the aircraft's ground velocity vector.
The effect of drift-stabilizing the sight is to place the target marker symbol in the path of the computed impact point (neglecting cross trail) provided the aircraft's ground velocity does not change direction between pickle and release. In other words, the steering signals generated by the computer, after the pilot designates the target, will call for wings level flight. The pilot can still pull up, but he must do so with wings level.
Because the pilot is usually working very hard to steer the target marker symbol over the target, the aircraft is often in a bank at the time of target designation. In such a case the pilot must first unroll to a wings level attitude before initiating his pullup maneuver. The natural tendency of a pilot, however, is to pull straight back on the stick after designating the target, ignoring the wings level steering commands.